You can reformat existing paragraphs with left alignment and hanging indent - see Format - Paragraph Formatting - Paragraph Setup/Formatting
and it's help page.
A complete automatical writing with hanging indent is not possible. But something close to it could be realized.
Create a syntax highlighting language definition for your files where you want hanging paragraphs which contains an /Indent Strings =
specification with an indent string which either is really correct or will never be found in a text you write.
Enable the Auto Indent
feature at Configuration - Editor Display - Formatting
- see forum topic Partial Auto Indent
for an explanation why this should be done.
According to my step by step list at forum topic extension based tab settings problem
specify the tab stop value and indent settings you want for the hanging indent for your files with extension ??? or use the default if you don't want something special.
Now after all that preparations you should be able to start a new paragraph at column 1, after pressing RETURN at end of line 1, you have to press once the TAB key to manually indent the second line with the specified settings.
All further lines are then automatically indented with the specified settings when you press key RETURN at the end of the line.
If you want to start a new paragraph, you must press once (for a tab) the key BACKSPACE or the hot key for Edit - Delete - Delete to Start of Line
(for indent spaces) to get the cursor back to start column 1 for the new paragraph.
With a small macro or template you can combine RETURN + TAB to a single key hit when the template or macro has an appropriate hot key. But I think, pressing RETURN and then TAB is faster then pressing the key combination for the macro or template.